The present invention relates generally to a support device that allows for hands-free operation of an electrical test probe. The support device is preferably adherable and may be used with a locater tool.
Electrical test probes are used to provide an electrical connection between electrical components and testing instruments such as oscilloscopes and other measuring, monitoring, diagnostic, and signal processing instruments. An electrical test probe generally consists of a probing head (also referred to as a “test probe head”), a cable, and a testing instrument connector. The probing head may have an integral or replaceable electrical test probe tip that is suitable for making an electrical contact with electrical components. A probe tip can be described as input structure, but would not include an amplifier. The testing instrument connector is suitable for connecting to a testing instrument. The probing head is attached to a first end of the cable and the testing instrument connector is attached to the opposite end of the cable.
To maintain contact with traces, leads, legs, pins, vias, or other connection points of electrical components, a test probe tip must be held in place after it is positioned. Generally a user uses at least one hand to place (position and hold) the traditional test probe tip. With only one unoccupied hand, the user is presented with significant logistic problems. For example, it is difficult or impossible for a single user to monitor multiple channels. Another example is that it is difficult or impossible for a single user to monitor a single channel and simultaneously make adjustments to an oscilloscope. It is also difficult or impossible for a single user to place the test probe tip and solder it in place and/or provide solder in reinforcement.
One solution to the problem of positioning and holding test probes is to use alternative test probe tips. One type of alternative test probe tip is a grabber tip that can be used to grab or grip certain types of electrical components. A securely placed grabber tip can generally maintain its position without being held by the user. If the grabber tip is used with a light-weight probing head, then the user is able to use the combination “hands free.” Grabber tips, however, tend to limit bandwidth performance because the mechanism for securing the grabber tip is inside the signal path. Grabber tips are also not very adaptable, are delicate, are expensive, are harder to find than traditional test probe tips, and pose significant electrical issues.
Another solution is the use of an off-board device for positioning and holding test probes. An off-board solution is a device that is generally located far from the contact point to be probed (far proximity). Off-board devices are generally heavy so that they can be stabilized using gravity. One exemplary off-board solution is known as the PROBE BUDDY™. The PROBE BUDDY™ has a bendable “neck” with a weighted “foot” at one end and a holder at the other end. The holder holds the probing head. A user can bend the neck until it is in the correct position to hold the test probe tip of the probing head in electrical contact with the electrical component to be probed. Because of its weight, the foot is positioned off the circuit board. This requires extra space substantially adjacent the circuit board. In actual use, the PROBE BUDDY™ is hard to position correctly.
Another problem with using test probes occurs when a difficult connection is finally made and then the circuit board shakes or the user sneezes. If the circuit board is even slightly knocked, the connection is lost. Grabber tips can be used to solve this problem. Off-board solutions such as the PROBE BUDDY™, however, would hold the probing head in place while the circuit board moves. The relative movement between the tip and the board would cause the connection to be lost.
Some of the problems of the PROBE BUDDY™ have been solved by devices such as those disclosed in European Patent Application No. 0232614A1 to Janko (the “Janko reference”) and U.S. Pat. No. 6,462,529 to Campbell (the “Campbell reference”), both of which disclose devices for supporting a probing head on a circuit board. These devices can be thought of as medium proximity solutions. Because they are lightweight, they can sit onboard the surface of the circuit board. However, they still use gravity to keep the connection.
The Janko reference is directed to a probing head having a test probe tip and two integral legs that together form a tripod that supports the probing head. The two legs may include nonskid tip surfaces or end pieces or boots made from a soft, non-slip material. The Janko device, however, is extremely limited in that it is an integral unit. In other words, the entire unit must be purchased and used as a whole. Old test probes that are still functional could not take advantage of the legs. Further, if the Janko device did not have a desired test probe tip, the user would be forced to choose a test probe tip Janko did have or not to use the legs. The Janko device is also directed to a downwardly extending tip and legs extending laterally in the same general direction as the tip. This configuration limits the Janko device to uses where the surface to be probed is the upper surface of a component.
The Campbell reference is directed to legs for forming a tripod with an electrical test probe tip. The legs and test probe tip both may be positioned on the circuit board such that they support the probing head for hands-free operation of an electrical test probe. The Campbell device preferably includes at least one support member and an adapter. The adapter is for connecting the support members to the electrical test probe. The support members and the test probe tip of the electrical test probe together form a tripod to support the electrical test probe for hands-free operation.
The Janko and Cambell devices both work on the principle that the entire probing head is supported on the circuit board. But as circuit boards become more crowded (or shrink in size), there is less room for these types of support devices.
Another solution is the Cascade Microtech Inc. probe holder. The Microtech Inc. probe holder, however, is not really suitable for manual probing, is complicated to use, and is very expensive.